Chusetts



(No Model.)

B. M. HUNTER.

METHOD OF OPERATING ELECTRIC RAILWAYS.

AN 7 0 M W n N H J A1 w M 2 (NM NH 4 I H /L 0 J2 m v\ x. N

UNITED STATES PATENT OEEIcE.

RUDOLPH M. HUNTER, OF PHILADELPHIA, PENNSYLVANIA, ASSIGNOR TO THETHOMSON-HOUSTON ELECTRIC COMPANY, OF BOSTON, MASSA- CHUSETTS.

METHOD OF OPERATING ELECTRIC RAILWAYS.

SPECIFICATION forming part of Letters Patent No. 424,607, dated April 1,1890.

Original application filed November 30, 1886, Serial No. 220,240.Divided and another application filed April 2 1889, Serial No.

305,771. Again divided and this application filed October 10, 1889.Serial No. 326,632. (No model.)

To all whom it may concern.-

Be it known that I, RUDOLPH M. HUNTER, of the city and county ofPhiladelphia, and State of Pennsylvania, have invented an Improvement inthe Method of Operating Electric Railways, of which the following is aspecification.

My invention has reference to a method of operating electric railways;and it consists of certain improvements, all of which are fully set outin the following specification, and shown in the accompanying drawings,form ing a part thereof.

This application (Case 115) is a division of my application, Serial N 0.305,771, of April 2, 1889, which in turn was a division of myapplication, Serial No. 220,240, filed November 30, 1886.

In one portion of my invention all of the current passing down the lineis caused to pass through the cars on a section of conductors; but allthe current over and above that which should properly pass through themotors is shunted around the motors automatically, the regulation beingindependent of manual exercise of judgment.

It is immaterial to my invention how the means for shunting the excessof current around the motor may be made or operated, and while I preferto cause the regulation to take place automatically the spirit of theinvention may be carried out even when the operator on the car isrequired to control the devices.

The generator for supplying the current to the line or workingconductors is a shunt or compound-wound machine for generating a varyingcurrent with a constant potential. Aside from the automatic switches forshunting the excess of current around the motor, there are variableresistances on the cars for controlling the speed and power of the motoror for stopping the car, which variable resistances are operated byhand. Where the railway is short and the number of cars comparativelyfew, the automatic-shunting devices on the cars could be dispensed with.

In operating electric railways on constant potential circuits there areseveral important results taking place automatically and dependent uponhand regulation in certain other parts of the system. Theline-conductors supply current to the motors on the various cars, whichare connected in parallel or multiple arc with each other, and eachdraws its supply of current from the same conduct ors and source ofelectrical energy. The generator at the central station is a self-reulating shunt or compound-wound dynamoelectric machine and feeds theline conductors with more or less current in volume or amperes whilemaintaining the constant potential. It is evident that I have here anumber of traveling or moving resistances in in the motors andregulators on the cars, and it is also evident that these resistancesare constantly varying, not only from the variations intheir speed andstoppages, but also from the fact that as the motor moves farther fromthe generator the increased line-resistance is to be added to themotor-circuit on the car. The resistances which are thus constantlyvarying as to position and amount cause a varying demand upon thegenerator in the central station, and this demand is met by the use of aself-regulating constant potential generator. 'The varying demand iscomplex and must be met, for if on a railway employing twenty-five carstwenty were suddenly stopped the large amperage for the twenty-five carswould have to go through the remaining five cars it the source of supplywere not automatically cut down to that necessary for the live cars. Itis true that resistances on the cars might be resorted to; but themotors on the cars might be burned out before the operator realized thedanger.

In the drawings, Figure l is a plan view of an electric railwayembodying myinvention, and Fig. 2 is an enlarged sectional elevation ofone of the motor-cars.

A and B are two lines of working-conductors, and are made in sections.The conductors may be either the rails or auxiliary conductors,suspended exposed on the surface of the road-bed or placed in a slottedconduit.

One end of the conductorAis connected with one terminal of the generatorB, and the opposite end of the corresponding section of conductor B isconnected by wire a with the adjacent end of the next section ofconductor A, 7

and so on. In these conductors a are located magnets A, which operateswitches A so that when no motors are in circuit with a section B theswitch A will operate to close the break between two succeeding sectionsA, and vice versa. The distant end of the A conductor is connected withthe other terminal of the generator B. I

It is evident that if we were to only consider one section of therailway, which might be five miles long, the conductors a, from B wouldconnect directly with the return-wire B and this would form an equalresistance-circuit, as set out in my patent, No. 381,555,0f April 24,1888. The generator 13 may be supplied with the regulator 17, or othersuitable regulating device, and is shunt or compound wound, so as to beself-regulating and give a varying current in amperes, while maintaininga substantially constant potential.

0. are electrically-propelled vehicles, cars, or locomotives, and may beconstructed in any manner desired. These cars maintain electricalconnection with the conductorsA B by suitable current-collecting brushesJ.

D are the electric motors on the said cars, and J is the motor-circuit,which may have a resistance-changerJ under the control of the operator,to vary the speed or power of the motor or stop the car, and acurrent-reversing switch J 3 for reversing the current passing to themotor.

E is a shunting device for shunting more or less of the line-currentaround the motors on each car. It consists of a shunt-circuit e inmultiple-arc connection with the motor D and having a variableresistance 6, more or less of which is put into or out of circuit by aswitch E operated by an electro-helix and core E, which helix is in theshunt-circuit and directly controlled by the current therein. To reducethe amount of current passing through the helix, an additional shunt E(see Fig. 1) might be placed in the shunt earound the helix. It isimmaterial to my invention how this regulator is made so long as itaccomplishes the objects sought to be covered. It will now be understoodthat if a section of conductors be supposed to hold in multiple-arcconnection five cars one-fifth of all the current will vpass througheach motor or car. If,.now, two cars are from any cause taken otf thesection, the remaining three cars will still only receive three-fifthsof the entire current, as their shunting devices E respond to shunttwofifths of the current around the motors on the cars; hence the totalnormal resistance to the line is constant, and the current passing downthe line is in no wise diminished. This regulation is automatic; but itis evident that the result might be accomplished by operating theshunting responds to one section of the above-described system,) as theregulator-shunt device would operate to increase or reduce the currentflowing through the motor to compensate for the change in the resistanceof the line according as the motor is near to or Very far from thegeneration-station. It is my object to use comparatively high tensioncurrents and working-conductors of small sectional area. In long lines,where a large number of cars are on circuit, this line-resistance is animportant factor in automatic regulation. When the switches on the carare operated by hand, the resistance between the two conductors A and Bof the railway variesproportionally, and likewise the resistance at theterminals of the generating-dynamo varies, and thereby causes theinstant automatic regulation of the volume of current to suit thedemand, maintaining the same potential and voltage.

I have described the general features of my improvements; but it is tobe understood that I'do not limit myself to the details, as they may bemodified in-various ways without departing from my invention.

j In this application I do not claim the series multiple system ofoperating electric railways, as such method and construction formsubject-matter of my application, Serial No. 192,187, filed February17,1886; nor do I claim the arrangement of supporting-wheels or connectionof the motor with the rear wheels, as the same form subject-matter of myapplications of which this is a division and my applications, SerialNos. 215,199, of September 23, .1886; 224,150, of January 12, 1887, and250,842,0f September 27, 1887.

Having now described my invention, what I claim as new, and desire tosecure by Letters Patent, is

1. The method of controlling two or more electric motors in multiple-arcconnection, consisting in shunting more or less of the current aroundsaid motors, according as the numbers of said motors in circuit decreaseor increase.

. 2. The method of controlling an electric motor in passing from asection of conductors of one current strength to another section ofanother current strength, which consists in shunting more or less of thecurrent around said motors, according as the current is stronger orweaker in the different sections.

3. The method of operating an electric railway, consisting inmaintaining two or more electrically propelled cars in groups and other,and two or more such groups of cars I u 7 I coupled in multiple-arcconnection with each I around the motor on each car of a group inaccordance with the increase or decrease in the number of cars in thegroup to maintain the current passing through the motors remainingnormally constant.

4. The method of operating an electric railway, consisting in supplyingto a conductor or conductors extending along the railway a current ofsubstantially-constant potential and Varying Volume, and feeding saidcurrent at Various places along the conductor or conductors to a seriesof electric motors on cars traveling on the railway, and which motorsare connected in parallel with each other, varying the resistance of themotor-circuits, and thereby the total line-resistance, by handregulation on the cars to vary the speed or power or stop the travel ofthe cars, and automatically Varying the volume of current supplied tothe conductor or conductors by the generator in accordance with saidvarying demand and at the same time maintaining the potential of thecurrent substantially the same.

5. The method of operating an electric railway, consisting in supplyingelectric current of constant potential to the line, maintaining two ormore electrically-propelled cars in groups and coupled in multiple-arcconnection with each other, and two or more groups of cars coupled inseries connection with each other and shunting more or less of thecurrent around the motor on each car of a group in accordance with theincrease or decrease in the number of cars in the group to insure thecurrent passing through the motors remaining normally constant.

6. The method of controlling two or more electric motors in multiple-arcconnection, consisting in maintaining a circuit of constant potentialand in shunting more or less 'of the current around said motors,according as the number of said motors in circuit decrease or increase.

In testimony of which invention I have hereunto set my hand.

RUDOLPH M. HUNTER. WVitnesses:

ERNEST HOWARD HUNTER, O. S. CHAMPION.

